Cold-stunned turtles suffer Thanksgiving Day massacre

Thursday

Nov 29, 2018 at 6:00 AM

WELLFLEET — Global warming is a likely cause of the huge number of cold-stunned sea turtles that washed up on beaches frozen and mostly dead on Thanksgiving Day.

The Massachusetts Audubon Wellfleet Bay Wildlife Sanctuary, which is permitted by the National Oceanic and Atmospheric Administration to handle endangered Kemp’s ridley turtles, has been at the center of a sort of Thanksgiving Day massacre.

That day, 85 turtles, mostly the plate-sized Kemp’s ridleys — the most endangered sea turtle in the world — were recovered from Cape beaches, said Jenette Kerr, communications coordinator for the sanctuary. Almost all of them were dead, victims of the rapid drop in water temperature in Cape Cod Bay, cause of the “cold stunning,” a form of hypothermia.

“There was a dramatic killing freeze,” Kerr said.

Between Wednesday, Nov. 21, and Monday, 584 turtles were recovered by some of the 200 volunteers who have been trained by the sanctuary, Kerr said.

This year will likely see the second highest number of turtle strandings in the sanctuary’s history, Kerr said. The highest number occurred in 2014, when a record 1,246 were brought in dead and alive during the winter months.

Up until this year, 2015 had the second highest number, with 600 cold-stunned turtles found over several months, she said.

More turtles are becoming cold-stunned for two main reasons, according to Mark Faherty, the science coordinator at the sanctuary.

One is that there are more turtles due to conservation efforts. But on the negative side, he said, the Gulf of Maine is warming faster than other water bodies and so these turtles, which typically live in the tropical Gulf of Mexico, are increasingly able to survive the warm summer months in the Gulf of Maine. If the turtles leave New England in time they are fine. But the ones who become stuck in the confusing geography of Cape Cod Bay fall prey to the cold, Faherty said.

Usually, most turtles recovered by sanctuary volunteers in November are cold-stunned but alive, and can be rehabilitated at the New England Aquarium, Kerr said. By the end of December, most found on Cape shores — usually the bayside beaches from Barnstable to Truro — are dead because they’ve been here too long, she said.

What’s different about this year was the dramatic drop in water temperature, Kerr said. Other than that, it’s a typical Cape Cod story, she added.

Most cold-stunned turtles are Kemp’s ridleys, but a huge loggerhead, weighing almost 300 pounds, was rescued alive this past weekend at Great Island in Wellfleet, Kerr said. Larger animals take longer to succumb to the cold. A thresher shark was also found dead in Wellfleet recently; these species also die in cold water, Faherty said.